Integrated Haptic Output and Touch Input System

Abstract

An electronic device is configured to provide localized haptic feedback to a user on one or more regions or sections of a surface of the electronic device. The localized haptic feedback is provided by an array of piezoelectric haptic actuators below the surface of the electronic device. Actuators within the array of piezoelectric haptic actuators are separately controllable by a control circuit layer. The control circuit layer includes control circuitry, a master flexible circuit which passes between rows of actuators, and an array of slave flexible circuits. Each slave flexible circuit is connected to the master flexible circuit and an actuator. In further examples, the array of piezoelectric haptic actuators provides a unified structure for detecting touch and force inputs.

What is claimed is: 
     
         1 . An electronic device, comprising:
 a cover sheet;   a display positioned below the cover sheet;   a chassis positioned below the display;   an array of piezoelectric actuators positioned below and coupled to the chassis; and   a flexible circuit assembly electrically coupled to each of the array of piezoelectric actuators, comprising:
 a master flexible circuit positioned along a row of piezoelectric actuators; 
 a first slave flexible circuit electrically coupled to the master flexible circuit and electrically coupled to a first of the array of piezoelectric actuators; 
 a second slave flexible circuit electrically coupled to the master flexible circuit and electrically coupled to a second of the array of piezoelectric actuators. 
   
     
     
         2 . The electronic device of  claim 1 , further comprising control circuitry electrically coupled to the master flexible circuit and configured to generate control signals to selectively actuate the array of piezoelectric actuators. 
     
     
         3 . The electronic device of  claim 1 , wherein each of the array of piezoelectric actuators comprises:
 a piezoelectric substrate having a first surface and a second surface parallel to the first surface;   a first electrode formed on the first surface; and   a second electrode formed on the second surface and a portion of the first surface.   
     
     
         4 . The electronic device of  claim 3 , wherein the first electrode and the second electrode are formed by at least one of vapor deposition, sputtering, printing, and roll-to-roll processing. 
     
     
         5 . The electronic device of  claim 3 , wherein the first electrode and second electrode are formed by plating the piezoelectric substrate with nickel. 
     
     
         6 . The electronic device of  claim 1 , wherein the master flexible circuit, the first slave flexible circuit, and the second slave flexible circuit each comprise:
 a flexible substrate; and   one or more conducting traces formed on or within the flexible substrate.   
     
     
         7 . The electronic device of  claim 6 , wherein the flexible substrate comprises at least one of polyimide and polyethylene terephthalate. 
     
     
         8 . The electronic device of  claim 6 , wherein the one or more conducting traces comprise at least one of silver, copper, constantan, and karma. 
     
     
         9 . The electronic device of  claim 6 , wherein the first slave flexible circuit comprises a first conductive trace coupled to a control signal and a second conductive trace coupled to a reference voltage. 
     
     
         10 . The electronic device of  claim 6 , wherein:
 the first slave flexible circuit comprises a first conductive trace coupled to a control signal; and   the chassis is coupled to a reference voltage.   
     
     
         11 . A haptic actuator module, comprising:
 a piezoelectric substrate defining a top surface and an opposing bottom surface;   a top electrode coupled to the top surface;   a bottom electrode coupled to the bottom surface; and   a control system, comprising:
 a control circuit configured to generate control signals to induce a voltage across the piezoelectric substrate and cause the piezoelectric substrate to compress along a direction; 
 a flexible circuit electrically connected to the control circuit and at least one of the top electrode and the bottom electrode, comprising:
 a master control flex connected to the control circuit; 
 a first slave control flex connected to the master flex and at least one of the top electrode and the bottom electrode; 
 a second slave control flex connected to another haptic actuator. 
 
   
     
     
         12 . The haptic actuator module of  claim 11 , wherein:
 a portion of the bottom electrode is deposited on the top surface of the piezoelectric substrate; and   the first slave control flex is connected to the top electrode and the bottom electrode at the top surface of the piezoelectric substrate.   
     
     
         13 . The haptic actuator module of  claim 12 , wherein the first slave control flex is coupled to the top electrode and the portion of the bottom electrode by an anisotropic conductive film. 
     
     
         14 . The haptic actuator module of  claim 11 , wherein:
 the top electrode is electrically connected to a support structure;   the support structure is biased with a reference voltage level; and   the first slave control flex is coupled to the bottom electrode and configured to provide a control signal to the bottom electrode.   
     
     
         15 . The haptic actuator module of  claim 14 , wherein the support structure is coupled to the top electrode by an isotropic conductive film. 
     
     
         16 . The haptic actuator module of  claim 11 , wherein:
 the first slave control flex is split at an end into a first portion and a second portion;   the first portion is coupled to the top electrode and configured to provide a control signal to the top electrode; and   the second portion is coupled to the bottom electrode and configured to provide a reference voltage level to the bottom electrode.   
     
     
         17 . The haptic actuator module of  claim 16 , wherein the first portion is coupled to the top electrode by a first isotropic conductive film and the second portion is coupled to the bottom electrode by a second isotropic conductive film. 
     
     
         18 . A method for connecting an array of piezoelectric haptic actuators to control circuitry, the method comprising:
 applying an electrically conductive bonding agent to a master flex member;   aligning a first slave flex member with the master flex member;   aligning a second slave flex member with the master flex member;   bonding the first slave flex member and the second slave flex member with the master flex member;   wherein:
 the master flex member is positioned along a row of slave flex members including the first slave flex member and the second slave flex member; 
 the master flex member is configured to provide a first control signal to the first slave flex member and a second control signal to the second slave flex member; 
 the first slave flex member is configured to provide the first control signal to a first piezoelectric haptic actuator; and 
 the second slave flex member is configured to provide the second control signal to a second piezoelectric haptic actuator. 
   
     
     
         19 . The method of  claim 18 , wherein:
 the electrically conductive bonding agent comprises a solder paste; and   the bonding the first slave flex member and the second slave flex member with the master flex member comprises heating the first slave flex member, the second slave flex member, and the master flex member.   
     
     
         20 . The method of  claim 19 , wherein the heating the first slave flex member, the second slave flex member, and the master flex member comprises heating in a reflow oven. 
     
     
         21 . The method of  claim 18 , wherein:
 the electrically conductive bonding agent is a first electrically conductive bonding agent; and   the method further comprises:
 applying a second electrically conductive bonding agent to the first slave flex member; and 
 bonding the first piezoelectric haptic actuator to the first slave flex member. 
   
     
     
         22 . The method of  claim 21 , wherein:
 the second electrically conductive bonding agent comprises an anisotropic conductive film; and   the bonding the first piezoelectric haptic actuator to the first slave flex member comprises placing the first piezoelectric haptic actuator on the second electrically conductive bonding agent.   
     
     
         23 . The method of  claim 18 , further comprising forming the first piezoelectric haptic actuator by:
 depositing a first electrode on a first side of a piezoelectric substrate; and   depositing a second electrode on a second side of the piezoelectric substrate and a portion of the first side of the piezoelectric substrate.   
     
     
         24 . An electronic device comprising:
 an enclosure;   a display positioned within the enclosure;   an input region positioned within the enclosure; and   a sensor structure positioned below the input region, comprising:
 a piezoelectric substrate; 
 a sensing layer comprising a plurality of drive electrodes and a plurality of sense electrodes; and 
 a connection layer comprising a plurality of conductive elements connected to the plurality of sense electrodes by vias; 
   wherein:
 the sensor structure is configured to detect a location of a touch within the user input region and to estimate an amount of force corresponding to the touch; 
 the drive electrodes and the sense electrodes are coplanar; and 
 the conductive elements are not coplanar with the sense electrodes. 
   
     
     
         25 . The electronic device of  claim 24 , further comprising touch sensing circuitry operatively coupled to the sensor structure and configured to determine the location of the touch. 
     
     
         26 . The electronic device of  claim 25 , further comprising force sensing circuitry operatively coupled to the sensor structure and configured to output a signal in response to the amount of force exceeding a given threshold. 
     
     
         27 . The electronic device of  claim 26 , wherein the given threshold is dynamically configurable. 
     
     
         28 . The electronic device of  claim 26 , wherein the touch sensing circuitry and the force sensing circuitry form a combined touch and force sensing circuitry. 
     
     
         29 . The electronic device of  claim 24 , wherein the sensor structure is further configured to output haptic feedback to the input region. 
     
     
         30 . The electronic device of  claim 24 , wherein the sensing layer comprises the plurality of drive electrodes arranged in rows and the plurality of sense electrodes arranged in columns. 
     
     
         31 . The electronic device of  claim 30 , wherein the plurality of drive electrodes and the plurality of sense electrodes are coplanar. 
     
     
         32 . The electronic device of  claim 31 , wherein;
 each of the plurality of sense electrodes spans a length of a column;   two or more of the plurality of drive electrodes are disposed between pairs of sense electrodes; and   a row of drive electrodes is electrically connected together.   
     
     
         33 . The electronic device of  claim 30 , wherein the plurality of drive electrodes and the plurality of sense electrodes are non-coplanar. 
     
     
         34 . The electronic device of  claim 24 , wherein:
 the piezoelectric substrate is a first piezoelectric substrate; and   the sensor structure further comprises a second piezoelectric substrate coplanar to the first piezoelectric substrate.   
     
     
         35 . A method of detecting a touch and estimating an amount of force of the touch, the method comprising:
 detecting the touch with a sensor structure comprising a piezoelectric substrate;   detecting an electrical response caused by compression of the piezoelectric substrate with the sensor structure;   estimating the amount of force using the electrical response; and   outputting a signal indicating the estimated amount of force.   
     
     
         36 . The method of  claim 35 , further comprising determining a location of the touch with touch sensing circuitry coupled to the sensor structure. 
     
     
         37 . The method of  claim 35 , wherein the outputting the signal is in response to the estimated amount of force exceeding a given threshold. 
     
     
         38 . The method of  claim 37 , wherein the given threshold is a dynamic threshold. 
     
     
         39 . A user input device, comprising:
 a cover sheet comprising a user input surface; and   a sensor structure positioned below the cover sheet, comprising:
 a piezoelectric substrate; and 
 a sensing layer comprising a plurality of electrodes; 
   wherein the sensor structure is configured to detect a location of a touch on the user input surface and to estimate an amount of force corresponding to the touch.   
     
     
         40 . The user input device of  claim 39 , further comprising touch sensing circuitry operatively coupled to the sensor structure and configured to determine the location of the touch. 
     
     
         41 . The user input device of  claim 39 , further comprising force sensing circuitry operatively coupled to the sensor structure and configured to output a signal in response to the amount of force exceeding a given threshold. 
     
     
         42 . The user input device of  claim 39 , wherein the sensor structure is further configured to output haptic feedback to the user input surface. 
     
     
         43 . The user input device of  claim 39 , wherein the user input device is a trackpad. 
     
     
         44 . The user input device of  claim 43 , wherein the trackpad is incorporated into a laptop computer. 
     
     
         45 . The user input device of  claim 39 , wherein the user input device is operatively coupled to a mobile device. 
     
     
         46 . The user input device of  claim 45 , wherein the mobile device comprises a phone, a tablet, a speaker, a headphone, a mouse, or a musical instrument. 
     
     
         47 . The user input device of  claim 39 , wherein the user input device is a touch- and force-sensitive keyboard. 
     
     
         48 . The user input device of  claim 40 , wherein the touch sensing circuitry is configurable to define a touch-sensing region on the cover sheet. 
     
     
         49 . The user input device of  claim 48 , further comprising force sensing circuitry operatively coupled to the sensor structure and configured to define a force-sensing region wherein the force sensing circuitry outputs a signal in response to the amount of force exceeding a given threshold.